Laboratory approach to alleviate dynamic behavior of rock structure

This paper presents analysis of the behavior of rock under induced compressive stress states. Three types of rock namely; Barre granite, Berea sandstone, and Indiana limestone were studied in the laboratory under various rates and modes of applied stresses, utilizing an electrohydraulic servo control testing machine. The dynamic responses of these rock samples under the load were evaluated. Characteristic behavior of these rock materials were studied through analysis of specimens mode of failure, storing strain energy prior to failure, stress-strain characteristics, acoustic emission signature and total number of acoustic emissions (events) generated during loading and applied stress history. The mode of failure in each case was observed and photographed and an idealized failure mode and mechanism has been proposed. The results of the laboratory experiments indicated that the nature of applied stress and loading history has significant effect on strength and mode of failure in rock. Furthermore, the dynamic response of rock under the applied compressive stress can be alleviated by subjecting the rock structure to both a low rate of loading and an inhomogeneous stress field.